The present invention relates to a process for the densification of a porous structure consisting of filling the voids, gaps or cavities of a porous structure by introducing thereinto an identical or different material from that forming the structure. The filling of the cavities of the structure lead to an increase in the density thereof, which justifies the use of the word "densification".
The invention more particularly applies to the densification of fabrics or felts of a bidirectional or tridirectional nature, which can advantageously be used as a result of their high mechanical strength, their excellent thermal insulation capacity and their good resistance to impacts and abrasions for the production of brake disks.
Hitherto, the densification methods which have been used have consisted of immersing the structure to be densified in a liquid bath of pitch or pyrolyzable resins and then pyrolyzing the pitch or resin so as to rigidify the assembly, or placing the structure to be densified in a gas stream, such as a stream of gaseous hydrocarbons and then raising it to a high temperature, e.g. in such a way as to crack the gaseous hydrocarbons in order to obtain carbon or pyrolytic graphite, which can be deposited in the cavities of the structure. Unfortunately, the time necessary for performing these processes is generally too long, when it is desired to obtain a high density structure.